society > communication > telecommunication > radio communications > radio equipment > [noun] > radar apparatus > types of (3)
an instrument used for radio sounding, such as a radiosonde or ionosonde.
An instrument that obtains and transmits information about its surroundings from an inaccessible location, such as underground or underwater.
A radar designed to provide information about the roughness or the profile of a surface from the way it scatters the incident microwaves.